A tank is a tracked armoured vehicle designed for front-line action, combining strong offensive and defensive capabilities. For offense the tank carries a large calibre gun and machine guns while heavy armour and good all-terrain mobility provide protection for the tank and its crew.
Tanks were first manufactured during World War I in an effort to break the deadlock of trench warfare. The British Army realized that they required a vehicle that had the mobility to reach the enemy trenches over barbed wire and rough terrain, the armour to withstand small arms fire and shrapnel from artillery and the weaponry to suppress or destroy enemy infantry, machine gun nests and pillboxes.
Today, tanks are among the most formidable and versatile weapons on the battlefield. They are valued for their ability to engage a wide range of ground targets, including enemy tanks and fortifications, as well as their shock value against infantry. In the ongoing race for battlefield supremacy, tanks and armored tactics have undergone continuous evolution for nearly a century. Although the main battle tank is generally considered a key component of modern armies, recent thinking has challenged the need for such powerful and expensive weaponry in a period characterized by unconventional and asymmetric warfare.
Tanks seldom operate alone, being organized into armoured units. Despite their apparent invulnerability, without combined arms support tanks are vulnerable to specialized anti-tank artillery, helicopters and aircraft, enemy tanks, anti-tank and improvised mines, and (at short ranges) infantry.[1]
Perhaps the greatest tribute to the impact of the tank on modern warfare is the variety of methods that have been developed to destroy or neutralise them.
[edit] History
[edit] World War I: The tank is born
The first proposal for a tank was by the Austrian Oberleutenant Günther Burstyn who, in 1911, proposed a design for "motor artillery" (Motorengeschütz) with a turret, but his design never progressed beyond a German patent in 1912.[citation needed]
Tank or "landship" development, originally conducted by the British Navy under the auspices of the Landships Committee was sponsored by the First Lord of the Admiralty, Winston Churchill and proceeded through a number of prototypes culminating in the Mark I tank prototype 'Mother'.[2] The first tank to engage in battle was named "D1", a British Mark I, during the Battle of Flers-Courcellette on 15 September 1916.[3] For further information on British World War I tank actions, see Tanks in World War I.
In contrast to World War II, Germany fielded very few tanks during WWI, with only 15 of the A7V type being produced in Germany during the war.[4] The first tank versus tank action took place on 24 April 1918 at Villers-Bretonneux, France, when three British Mark IVs met three German A7Vs.
Mechanical problems, poor mobility and piecemeal tactical deployment limited the military significance of the tank in World War I and the tank did not fulfil its promise of rendering trench warfare obsolete. None the less, it was clear to military thinkers on both sides that tanks would play a significant role in future conflicts.[2]
[edit] Interwar years: Experiments
In the inter-war period tanks underwent further mechanical development and, in terms of tactics, J.F.C. Fuller's doctrine of spearhead attacks with massed tank formations was the basis for work by Heinz Guderian in Germany, Percy Hobart in Britain, Adna R. Chaffee, Jr. in the U.S., Charles de Gaulle in France, and Mikhail Tukhachevsky in the USSR. All came to similar conclusions, but in the Second World War only Germany would put the theory into practice on a large scale, and it was their superior tactics and French blunders, not superior weapons, that made blitzkrieg so successful in May 1940.[5] For information regarding tank development in this period, see tank development between the wars.
Germany, Italy and the Soviet Union all experimented heavily with tank warfare during their clandestine and/or 'volunteer' involvement in the Spanish Civil War, which saw some of the earliest examples of successful combined arms - such as when Republican troops, equipped with Russian-supplied medium tanks and supported by aircraft, eventually routed Italian troops fighting for the Nationalists in the seven-day Battle of Guadalajara in 1937.[6]
[edit] World War II: Blitzkrieg and combined arms
World War II was the first conflict where armoured vehicles were critical to success on the battlefield. During the German Invasion of Poland (1939) the Germans used a combination of Panzer I (a training tank), Panzer II light tanks, and captured Czechoslovakian tanks (Panzer 35(t) and Panzer 38(t)). Early war German tanks sacrificed firepower and protection for mobility and reliability. In contrast, the French had good tanks like the Somua S35 and Char B1 but employed a defensive strategy and had poor tank command and control systems, lacking radios in many of their tanks and headquarters.[5] The French and British used a range of tank designs with different roles (see British tank classification). One of the more successful British tanks of the war was the Matilda tank.
The German doctrine of blitzkrieg or "Lightning War" made use of radios in all of the tanks to provide command and control, which made them more effective tank for tank than their Allied opponents in the Battle of France, despite the Allied machines being more than a match for the panzers one-on-one. German tanks bypassed enemy strong-points and could radio for close air support to destroy them, or leave them to the infantry on foot. A related development, mechanized infantry, allowed some of the troops to keep up with the tanks and create (for the period) highly mobile combined arms forces.
By 1941, the Germans had the newer Panzer III and Panzer IV tanks with which to invade the Soviet Union in Operation Barbarossa. In an echo of the Battle of France the Soviets had several good tanks and one superb tank design, the T-34. German crews were initially shocked by the excellent all-round performance of the T-34 and the protection and firepower of the KV-1. As before, the rigid Soviet command structure and poor leadership allowed their machines to be surrounded and destroyed in detail, but the Germans could not precipitate the same tactical and strategic panic as they had in France; instead they found an enemy that doggedly kept fighting without food, water and communications.[7] Despite early successes against the Soviets, the Germans began up-gunning their Panzer IVs, and eventually built larger Panther and Tiger tanks to (ultimately unsuccessfully) deal with the Soviet tank threat.
When entering WWII American mass production capacity enabled her to rapidly construct thousands of relatively cheap Sherman tanks. A compromise all round, the Sherman was reliable and formed a large part of the Anglo-American combined arms forces, but they were easily destroyed by the superior German Panther and Tiger tanks. In terms of tank warfare, large numbers allowed the Americans to overrun the German forces during the Battle of Normandy. The Sherman Firefly was introduced to improve the Sherman's firepower, but concerns about protection remained.
Tank chassis were adapted to a wide range of military jobs, including mine-clearing and combat engineering tasks. Specialised self-propelled guns were also developed: artillery, tank destroyers, and assault guns were essentially cheap, stripped down tanks carrying large calibre guns, often in a fixed hull mounting. German and Soviet assault guns, like the SU-122 had the heaviest guns mounted in vehicles, but by the end of the war a gun turret was recognised as the most effective mounting for the main gun to allow movement in a different direction from firing. Improved suspension systems were developed that allowed better cross-country performance and firing while moving. Systems like the earlier Christie or later torsion bar suspension developed by Ferdinand Porsche dramatically improved the tank's cross-country performance and overall mobility.[8]
By the end of the war all forces had dramatically increased their tanks' firepower and armour; for instance, the ten ton Panzer I had only two machine guns; at war's end, the standard German medium tank, the Panzer V or Panther tank mounted a powerful, high-velocity 75 mm gun and weighed forty-five tonnes but had mobility comparable to the Panzer I.
[edit] The Cold War: Tanks in the arms race
During the Cold War, the two opposing forces in Europe were the Warsaw Pact countries on the one side, and the NATO countries on the other side. The Warsaw Pact was seen by the West as having an aggressive force outnumbering the NATO forces and tank development proceeded largely as it had during WWII to maintain the balance of power. The essence of tank designs during the Cold War had been hammered out in the closing months of World War II. Large turrets, capable suspension systems, greatly improved engines, sloped armour and large caliber (100mm+) guns were all introduced to tanks during WWII. Tank design during the Cold War built on this foundation and included improvements to fire control, gun stabilisation, communications and crew comfort. Armour technology progressed in an ongoing race against improvements in anti-tank weapons, especially antitank guided missiles like the TOW.
Medium tanks of WWII gradually evolved into the Main Battle Tank of the Cold War and took over all tank roles on the battlefield. This transition happened gradually in the 1950s, as it was realized that medium tanks could carry guns (such as the US 90 mm, Soviet 100 mm, and the excellent British L7 105 mm) that could penetrate any practical thickness of armour plate at long range. The WWII concept of heavy tanks, armed with the most powerful guns and heaviest armour became obsolete, since they were just as vulnerable as other vehicles to the new medium tank guns. Likewise, WWII had shown that lightly-armed, lightly-armoured tanks were of little value in most roles; speed was not a substitute for armour and firepower.
The main battle tank (MBT) thus took on the role the British had once called the 'Universal tank', filling all battlefield tank roles. Among the classic tanks of the 1950s were the British Centurion, the Soviet T-55 series, and the US M48 series. These three basic vehicles were upgraded significantly over time and formed the bulk of the armoured forces of NATO and the Warsaw Pact throughout the Cold War. Some of them remain in use in the 21st century.
Although the basic roles and traits of tanks were almost all developed by the end of WWI, the performance, firepower and protection of twenty-first century tanks has increased by an order of magnitude over the early prototypes. Tanks have evolved dramatically in response to continually changing threats and requirements and especially in response to the threat of other tanks.
[edit] The 21st century: American Operations in Iraq from 2003 onward
As of 2005, there were 1,100 M1 Abrams used by the United States army in the course of the Iraq War, and they have proven to have an unexpectedly high level of vulnerability to roadside bombs.[9] A relatively new type of remotely-detonated mine, the explosively formed penetrator has been used with some success against American armoured vehicles (particularly the Bradley fighting vehicle). However, with upgrades to their armour in the rear, M1s have proven invaluable in fighting insurgents in urban combat (a role that tactics otherwise proscribe), particularly at the Battle of Fallujah, where the Marines brought in two extra brigades.[10] Britain deployed its Challenger 2 tanks to support its operations in southern Iraq.
[edit] Tank design
The three traditional factors determining a tank's effectiveness in battle are its firepower, protection, and mobility. In practical terms, the cost to manufacture and maintain a given tank design is also important in that it determines how many tanks a nation can afford to field.
Firepower is the ability of a tank to identify, engage, and destroy a target. Protection is the tank's ability to resist being detected, engaged, and disabled or destroyed by enemy fire. Mobility includes tactical (short range) movement over the battlefield including over rough terrain and obstacles, as well as strategic (long range) mobility, the ability of the tank to be transported by road, rail, sea, and/or air, to the battlefield.
Tank design is a compromise; it is not possible to maximize firepower, protection and mobility simultaneously. For example, increasing protection by adding armour will result in an increase in weight and therefore decrease mobility; increasing firepower by installing a larger gun will force the designer to sacrifice speed or armour to compensate for the added weight and cost.
Since WWII tank development has shifted focus from experimenting with large scale mechanical changes to the tank design to focussing on technological advances in the tank's subsystems to improve its performance.
- Further information: Tank classification
[edit] Firepower
With respect to tanks, firepower means the ability to rapidly detect, identify, engage and destroy targets on the battlefield.
The main weapon of all modern tanks is a single, large caliber (105 to 125mm) gun mounted in a fully traversing turret. The typical tank gun is a smoothbore weapon capable of firing armour-piercing kinetic energy penetrators (KEP), also known as armour-piercing discarding sabot (APDS), and high explosive anti-tank (HEAT) shells and/or anti-tank guided missiles (ATGM) to destroy armoured targets, as well as high explosive (HE) shells for engaging soft targets or fortifications. A modern type of tank ordnance arising from the close range urban combat in Iraq is a 120mm caliber "shotgun" round for the M1 Abrams which will fire 1100 tungsten pellets.[10]
A gyroscope is used to stabilise the main gun, reducing the effect of manoeuvring on accuracy. Modern tank guns are also commonly fitted with insulating thermal jackets to reduce gun-barrel warping caused by uneven thermal expansion, bore evacuators to minimise fumes entering the crew compartment and (less often) muzzle brakes to minimise the effect of recoil on accuracy and rate of fire.
Modern target detection relies on telescopic periscopes and sophisticated light intensification and thermal imaging equipment to improve fighting capability at night, in poor weather and in smoke. The accuracy of modern tank guns is pushed to the mechanical limit by computerized fire control systems. The fire control system uses a laser range-finder to detect the range to the target, a thermocouple, anemometer and wind vane to correct for weather effects and a muzzle referencing system to correct for gun-barrel temperature, warping and wear. Two sightings of a target with the range-finder enable calculation of the target movement vector. This information is combined with the known movement of the tank and the principles of ballistics to calculate the elevation and aim point that maximises the probability of destroying the target.
Usually, tanks carry small calibre (7.62 to 20mm) armament for short range defence where fire from the main weapon would be ineffective, for example when engaging infantry, light vehicles or aircraft. Typical mountings for these light weapons are coaxially with the main gun and on a roof mounting.
[edit] Protection
- See also: Anti-tank warfare
A tank's protection is the combination of its ability to avoid detection, to avoid being hit by enemy fire, its armour to resist the effects of enemy fire, and to sustain damage and complete its mission, or at least protect its crew. In common with most unit types, tanks are subject to additional hazards in wooded and urban combat environments which largely negate the advantages of the tank's long-range firepower and mobility, limit the crew's detection capabilities and can restrict turret traverse. Despite these disadvantages, tanks retain high survivability against previous generation RPGs in all combat environments by virtue of their armour. By contrast, tank survivability against newer generation tandem-warhead anti-tank missiles is a concern for military planners.[11]
[edit] Avoiding detection
A tank avoids detection using the doctrine of CCD: camouflage (looks the same as the surroundings), concealment (cannot be seen) and deception (looks like something else).
Working against efforts to avoid detection is the fact that a tank is a large metallic object with a distinctive, angular silhouette that emits copious heat and noise when mobile. Consequently, it's difficult to effectively camouflage a hull-up tank in the absence of some form of cover or concealment (eg. woods). The tank becomes easier to detect when mobile due to the large, distinctive auditory, vibration and thermal signatures of a powerplant with an output comparable to that of a diesel locomotive.[citation needed] Tank tracks and dust clouds also betray past or present tank movement. Powered down tanks are vulnerable to infra-red detection due to differences between the thermal conductivity and therefore heat dissipation of the metallic tank and its surroundings. At close range the tank can be detected even when powered down and fully concealed due to the column of warmer air above the tank and the smell of diesel.
Thermal blankets slow the rate of heat emission and camouflage nets use a mix of materials with differing thermal properties to operate in the infra-red as well as the visible spectrum. Camouflage attempts to break up the distinctive appearance and silhouette of a tank. Adopting a turret-down or hull-down position reduces the visible area of a tank as well as providing the added protection of a position in defilade.
[edit] Armour
To effectively protect the tank and its crew, tank armour must counter a wide variety of anti-tank threats. Protection against kinetic energy penetrators and high explosive anti-tank (HEAT) shells fired by other tanks is of primary importance, but tank armour must also aim to protect against infantry anti-tank missiles, anti-tank mines, bombs, direct artillery hits, and (less often) nuclear, bacterial and chemical threats, any of which could disable or destroy a tank and/or its crew.
Steel armour plate was the earliest type of armour. The Germans pioneered the use of face hardened steel during WWII and the Soviets also achieved improved protection with sloped armour technology. WWII developments also spelled the eventual doom of homogeneous steel armour with the development of shaped charge warheads, exemplified by the Panzerfaust and bazooka infantry weapons which were lethally effective, despite some early success with spaced armour.
British tank researchers took the next step with the development of Chobham armour, or more generally composite armour, incorporating ceramics and plastics in a resin matrix between steel plates, which provided good protection against early HEAT weapons. Magnetic mines led to the development of anti-magnetic paste and paint, squash head warheads led to Kevlar (or equivalent) anti-spall armour linings, and KEPs led to the inclusion of exotic materials like depleted uranium in the composite matrix. Reactive armour consists of small explosive "bricks" that detonate when damaged by HEAT fire, bending or disrupting the incoming molten metallic jet. Tandem warheads defeat reactive armour by causing the armour to detonate prematurely. Grenade launchers which can rapidly deploy a smoke screen and the modern Shtora soft-kill countermeasure system provide additional protection by disrupting enemy targeting and fire control systems.
The latest generation of protective measures for tanks are active protection systems, particularly hard-kill countermeasures. The Israeli TROPHY and Iron Fist, the American Quick Kill, and the Russian Drozd and Arena systems show the potential to dramatically improve protection for tanks against missiles, RPGs and potentially KEP attacks, but concerns regarding friendly fire against dismounted crew and nearby infantry remain.
[edit] Mobility
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